I have a set sitting here that I am gonna use if the are reliable. I remember some spring was breaking just can't remember which one it was. Or, should I just get a set of Z06 springs. The cam has .595 lift. Thanks, Andy

 

987's are OK but require machining of the cylinder head.

 

The 987 is an excellent spring for the correct application. I have 9,000 miles on mine and no problems at all. However, the max lift a cam should have with a 987 is normally .590, your cam at .595 is probably has too much lift. I would find another spring. This is based on what TEA told me about the way my 987's were set up on my Stage 2 heads. Depending on install height the max lift might be slightly different.

 

Crane makes a set of double springs where you don't have to machine the heads to make them fit. I would change the lifters while you're at it though.

 

The Z06 springs will not support .595" of valve lift. The Comp 987s are decent springs when used in the correct application. I would not recommend them for any sort of XE or XE-R based lobe trying to turn more than 6400 rpms.

I would look into the new Crane dual spring which fits into the factory spring pocket with no machine work.

Jason